REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 rl4:9 



approximately with the Hamilton of the counties farther west. 

 These shales are quarried at several points for local use as road 

 metal, but are of no great economic importance. 



Bellvale flags 

 The name Bellvale flags was given by Darton, in 1894, to the 

 hard, thin bedded gray sandstones which appear, overlying the 

 Monroe shales, in Schunemunk, Bellvale and Bearfort moun- 

 tains. Plant remains occur^ in these flags, and fix their age as 



middle Devonian. 



Schunnenmnk conglomerate 



Overlying the Bellvale flags in the mountains above named is 



a conglomerate of quartz and quartzite pebbles in a reddish 



silicious matrix. In 1894 Darton named this the Schunemunk 



conglomerate. He states that lithologically it differs from the 



Green Pond conglomerate in containing quartzite pebbles, which 



are absent in the latter. 



Newark beds 



The Newark beds of central and western New Jersey have 

 been divided by Klimmel into three superposed " formations." 

 These " formations " change in lithologic character as the New 

 York line is approached. Two of them, according to Ktimmel, 

 appear in Rockland county N. Y. They have not been mapped 

 separately however, and will not be separately treated in this 

 paper. Calcareous conglomerates, which appear near the north- 

 ern edge of the Newark area, have afforded some lime. 



IGNEOUS ROOKS 



Cutting certain of the formations above noted, granites and 

 other igneous rocks are frequently found in dikes or masses. 

 These igneous rocks vary greatly in composition and texture as 

 well as in economic importance. Of the many varieties present, 

 four show well marked and distinct types and occupy definite 

 areas of considerable size. For this reason they have been 

 assigned names as follows (being named after the localities at 

 which they are best developed): Yonkers gneiss, Harrison 



1 Martin, D. S. 

 Prosser, C. S. N, Y. acad. sci. Trans. 11:132-51. 



